This invention relates to a power plant cooling system for power plant equipment and more specifically to an integrated power plant cooling system utilizing multiple methods for generating a cooling medium to remove heat from an integrated skid of power plant cooling components. Typical cooling requirements of a power plant include generator cooling; lube oil cooling; transformer cooling; turbine inlet cooling; turbine inlet air cooling and intercooler cooling; and cooling for other miscellaneous components.
Many power plant components such as generators, lube oil systems, and transformers, require cooling to reject the heat generated by inefficiencies (windage, bearings, electrical heating, etc.), while additional cooling functions directly impact plant performance, as for example turbine inlet air cooling, compressor inlet air cooling or compressor intercooling. Individual cooling devices for these components typically utilize air or water-cooled heat exchangers. Generator cooling in existing configurations is provided by water or air supplied at ambient temperature. Lube oil systems usually utilize large air-cooled heat exchangers. Compressor intercoolers utilize water at ambient temperature. Transformer oils are cooled by rejecting heat to atmosphere using air-cooled heat exchangers.
Independent cooling skids are often utilized to provide the above cooling. Even when equipment is supplied with coolant from a common cooling system the equipment and coolers are sized for the highest ambient condition. This high temperature cooling fluid (air and water at ambient) causes the heat exchangers to have higher area and penalizes the over all power plant efficiency and cost.
Several means are commonly employed to provide cooling to power plant components. These methods are independent cooling skids with individual control systems. FIG. 1 illustrates independent cooling skids used to provide cooling in prior art power plant cooling systems. A power plant system 5 may include an air compressor 10, a gas turbine 15, a generator 20, and a transformer 25, which couples the generator 20 to supply electric power to the electrical grid system 30. Fuel is supplied to the gas turbine at 16 and compressed air at 17. Exhaust gas exits the gas turbine at 18.
Ambient air 35 is cooled through turbine inlet cooling skid 40 and provided at air compressor inlet 45. Hot compressed air 50 is extracted from an interstage 52 of the air compressor 10 and passed through compressor intercooling skid 55. Cooled air 56 is returned to a succeeding interstage 58 of the air compressor 10. Lube oil from the compressor 10, the gas turbine 15 and the generator 20 are cooled by lube oil cooling skid 60. Heat is removed from the lube oil on cooling skid 60 by an air-cooled heat exchanger using air at ambient temperature 65. Generator cooling water 22 circulates through a separate cooling skid 23 utilizing an air cooled heat exchanger drawing ambient air 24. Cooling for the transformer 25 is typically provided by transformer oil 26 passing through an air-cooled heat exchanger employing ambient air 27, the heat exchanger mounted on a separate transformer cooling skid 28. Turbine inlet cooling may be provided using chilled water provided by an independent mechanical compressor (not shown). In some cases, skids may be partially integrated systems with common water (not chilled).
As is always true in power plant determinations, the cooling requirements on each of the component systems is a function of site specific ambient and operating conditions, the performance available from each competing system and the costs required to implement and operate.
Accordingly, there is a need to provide an alternative cost effective method of integrating the independent power plant cooling skids into one single cooling system utilizing an absorption or a mechanical chiller providing chilled water for all power plant equipment requiring cooling, where controlled lower temperature cooling fluid (chilled water) will result in significant savings, simplify the plant operation and provide a reliable source of cooling medium.